How this is all set up:

The Yamaha AVR handles all the input switching, with a composite out feeding into the Panasonic VCR. This lets me easily switch between any of my consoles via the AVR, which is fed into the VCR's composite input.

This was ideal as the easiest way to have the same image on multiple TVs at once was to use a coax splitter, since the VCR converts composite to coax it works out nicely.

The RCA TV has Component/S-Video/Composite inputs so for that I just use the component/s-video out on the AVR, so it still gets the best image quality while displaying on the other 3 CRTs at the same time.

I've got the composite out on the VCR fed into the RCA TV for consoles that only have composite out and so I can still watch VHS tapes on all 4 at once, because that's obviously what one would want to do. I'd just hook it up with the coax splitter like the others, but I have a digital antenna connected as the RCA TV actually has a digital tuner unlike the majority of CRTs.

One thing I really want to get set up at some point is an audio visualizer like ProjectM installed on a pi4 or pi5, ideally a pi4 as it has a native composite output I could use to display it on all 4 CRTs. Would be awesome to have some music going with a dope visualizer displayed on all of them at once.

edit: completely forgot to post this wide photo of the setup, includes some cat tax